Signaling system



Sept. 28?, 1943. MQTE 2,330,357

SIGNALING SYSTEM Filed April 26, 1941 5 Sheets-Sheet l FIRST FLOOR RELAY NETWORK I6 I -uli i na LINE SWITCH u /L I70.)

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l'l'c TO OTHER STATIONS ON FIRST FLOOR IOSb STATION A 7 STATION 5 I INVENTOR. THOMAS H. MOTE M M W1; M

ATTORNEYS Sept. 28, 1943.

T. H. MOTE SIGNALING SYSTEM Filed April 26, 1941 SELECTOR SWITCH l2 5 She ets-Sheet 2 THOMAS P-LMOTE ATTORNEYS Sept. 28, 1943. T. H. MOTE SIGNALING SYSTEM Filed April 26, 1941 5 Shaets-Sheet 3 7 w wm 3 m E m m U vN H m E l l 5 m 3 mm 3.1]: 0% L m w a E m S B H G h w R m 0 E N N. 0 c

SIGNAL CONTROL PULSE GENERAIU SWITOHBOARD S Y E N R O W A Patented Sept. 28, 1943 psi SIGNALING SYSTEM Thomas H. Mote, Chicago, Ill., assignor to Automatic Electric Laboratories, Inc., a corporation of Delaware Application April 26, 1241, Serial No. 390,557

'8 Claims. (l. 177-353) The present invention relates tosystemsfor indicating the location of one or more persons or objects which may be located in different zones of a plural zone area, and more particularly to improvements in systems for providing accurate information as to the whereabouts of .a large numberof doctors who may be working on the different floors of a large hospital. An improved system of this character is disclosed and claimed the co-pending application, Serial No. 390,624, April 26, 1941, Alfred H. Belliveau, which is assigned to the same assignee as the present invention, and the present invention relates to improvements thereover. In the system disclosed in the Belliveau application, a display board is provided on each floor ofthe hospital and each board includes display registers or indicators of the pulse'controlled. rotatable drum type. The indicators'are divided into sets which are individual to the various doctors and are selectively con rollable through automatic switching equipment from control stations conveniently located on the floors of the hospital to indicate the 'floors where the doctors may be located, Control of automatic switching equipment and the selected indicators is effected through operation of signal transmitting devices of the conventional dial operated type which are individually provided'at the various control stations. Although the system issimple in arrangement, fully satisfactory in operation, and includes several improved and novel operating features; it requires an automatic switchfor each floor, the capacity of the system is limited to the provision of indi caters for a maximum of two hundred doctors, and upwards of three indicators or display registers are required for each doctor in each display board when the system is installed in a building having more than twenty floors or zones.

Accordingly, it is an object of the present invention to provide an improved system of the character described which has a-large posing capacity and in which the display units may be selected and controlled by the dialing of identification numbers having only a few digits.

It is a further object of the invention to provide an improved system of the character described, wherein the dialing operations required at the various control stations, in order to select a set of indicators and effect a change in "the setting thereof, are minimized by providing auxiliary pulse sending equipment which is automatically seized from the various control stations.

It is another object of the invention to provide an improved system of the character described, w erein the indicators of the display boards are selectively controlled through automatic concentration switches which are common to the various control stations.

It is a further object of the invention to provide an improved system of the character described, in which thenumber of indicators individual to each person or object posted on the display boards and required to indicate the zonelocations of suchpersons or objects is minimized.

It is still another object of the invention to provide an improved arrangement, whereby the switching facilities of the system may be utilized automatically to signal the doctors who may be located in the various zones to call a specified telephone operator located in the area.

It is a further and more specific object of the invention to provide such an arrangement, wherein each doctor who is wanted by the telephone operator is automatically signaled to that effect when he calls in from one of the control stations to effect a change in the setting of the indicators provided for his use on the display board.

In the illustrated embodiment of the invention each display unit is comprised of two pulse controlled electro -magnetically operated display registers or indicators. Each indicator includes an element having a normal or blank position and ten off-normal positions wherein the numerals from one to nine are displayed thereby. In order to select and control the operating magnets of the indicators, automatic switching equipment is provided which includes connector switches having access to the pulsing circuits which extend to the'oper'ating magnets of the indicators.

These circuits are so arranged that one of the two indicators in each unit is used as a tens indicatorand functions to display the tens digit of two-digit numbers identifying the various floors of the hospital, and the other indicator is used as a units indicator to display the units floor numbers. The pulsing circuits are further arranged to permit the indicators of a selected unit to be restored to their normal or blank positions in unison through the transmission of restoring pulses thereto over a common restoring pulse circuitl The resetting of the indicators of a selected unit is efiected'throu'gh the transmission of successive trains of reset pulses to the two indicators of the unit over separate reset pulse circuits. Inaccordanc'e with another feature of the invention, the tra'nsm'issionof the restoring and reset pulses is e'fie'cte'd through operation of automatic plural digit pulse senders which are individual to the control stations of each floor; The operation of each sender is effected in response to the selection of a setof indicators from one of the control stations located on the assoelated floor.

In accordance with another feature of the "invention, the indicator control facilities are coordinated with the telephone communication facillties of th hospital to .permit the paging of I doctors who may be occupied with various duties on. the several floors of the building. To this end, marking paths individual to the variou doctors and extending to the outlet contacts of the connector switches are provided. These paths may be selectively controlled from the branch exchange switchboard of the hospital so that when a doctor calls in from a control station to effect a change in the setting of the indicators provided for his use on the display boards, a signal is automatically transmitted to the control station in use. This signal informs the calling doctor that he should get in touch with the operator attending the branch exchange switchboard over the regular telephone facilities.

The novel features believed to be characteristic of the invention are set forth with particularity in the appended claims. The invention, both as to its organization and method of operation, together with further objects and advantages thereof, will best be understood by reference to the specification taken in connection with the accompanying drawings in which Figs. 1, 2, 3, 4 and 5, when combined in the manner shown in Fig. 6, illustrate a portion of the equipment provided in a system which includes the features of the invention briefly outlined above.

Referring now more particularly to the drawings, the system there illustrated comprises a plurality of display boards which are individual to the various floors of the hospital, and each of which is conveniently located for easy observation from any point in the corridor of the floor on which it is located. One such display board is indicated at 25 as being provided on the first floor of the hospital. This display board comprises a plurality of display units 26, 21, 28, 29, 30, etc., which individually correspond to the doctors whose locations are to be posted thereon. For example, the display unit 26 may be utilized to indicate the location of the doctor who is assigned the identification number 165, and the display unit 2! may be utilized to indicate the location of the doctor who is assigned the identification number 1'75. The various display boards are of identical arrangement and, as will appear more fully hereinafter, are so arranged that the units of each set which correspond to a particular doctor are controlled in unison. The individual display units of the display boards are also identical in arrangement, the illustrated unit 26 comprising a restoring relay Rdlfl and a pair of floor indicating display registers or indicators 408a and 49Gb. These registers are of the wellkno-wn electro-m chanical type, as shown, for example, in Figure 22 of Patent No. 2,234,684, granted March 11, 1941, to Harold C. Robinson and Martin L. Nelson, and each thereof is provided with a display drum which may be rotated from a normal or blank position to any one of ten cit-normal positions wherein the numerals one to nine and zero are respectively displayed thereby. More specifically, the register 400a is provided to display the tens digit of any floor number from ten to ninety-nine, and the register 4011b is provided to display the units digit of such floor numbers. The indicating drum of each display register 409 is mounted on a drive shaft to which rotary movement is imparted in one direction only by an associated pulse controlled operating magnet 40! through an associated ratchet and pawl or Geneva gear mechanism, not shown. The drive shaft of each register also carries a cam 403 which is arranged to control an associated set of commutating contacts 402 in the manner more fully explained hereinafter.

The control of the various display boards is effected from control stations which are conveniently located on each floor of the hospital. Thus the first fioor of the building is provided with two control stations A and B, each of which includes a signal transmitting device IEH, a connect key I04, and a pilot lamp I 05. The connect keys I04 are of the well-known locking type. Each signal transmitting device I0! is of the dial-operated type conventionally used in ubstations of automatic telephone systems, and comprises a set of pulsing springs I02.

The selection and selective control of the indicators included in the various display unit of the display boards is effected through the provision of automatic switching equipment, the major portion of which is common to all of the control stations in the hospital. More specifically, this equipment includes line switches individual to the various floors of the hospital and having access to a group of selector switches which, in turn, have access to five groups of connector switches through which the various display units may selectively be seized for control purposes. In the drawings, only a single line switch ll, individual to the control stations on the first floor, a single selector switch I2 and a single connector switch 13, are illustrated. The various connector switches of each group each have access to the display units individual to one hundred doctors and, since five groups are provided, the total posting capacity of the illustrated system is five hundred doctors. It will be understood, however, that by providing additional switching stages the capacity of the system may be expanded as desired. For example, if second selectors are interposed between the first selectors and the connectors, and additional groups of connectors are provided, the system capacity may be increased to five thousand doctors. The various line switches individual to the several floors are of conventional construction and arrangement and, accordingly, the line switch H has been only schematically illustrated in the drawings. This line switch, as Well as the line switches individual to the other floors, may be of the well-known plunger type or the well-known rotary type, as desired.

Each of the selector and connector switches includes a two-motion switching mechanism of the well-known Strowger type which is equipped with four banks of contacts each including one hundred contact points. The contacts making up each contact field are divided into ten levels of ten contact sets each, and each of the four banks has associated therewith a wiper which is carried by an associated wiper carriage structure of well-known construction and arrangement. Thus the selector switch [2 is illustrated in Fig. 2 of the drawings as comprising a contact field divided into four banks having the wipers 26L 262, 283 and 264 individually associated therewith. The trunks extending to the connector switches accessible to the selector switch 12, are each terminated at two sets of contacts in adjacent levels of the selector switch. Thus the trunk l8 extending to the connector switch I3, is multipled to the corresponding contact sets of the first and second levels of the contact field embodied in the selector switch l2. The purpose of this arrangement is to permit the doctors selectively to wipe out indications displayed by the indicators provided for their use, or to reset these indicators to display new indicationabydialing either of two identification numbers at any one of the control stations The manner in which this is accomplished is more fully considered in the following detailed description of the operation of the system. For the purpose of elevating the'enumerated wipers to a position opposite a desired level of bank contacts, and then rotating the same into engagement with a selected set of contacts of a selected level, vertical and rotary magnets 252 and 250 are included in the switching mechanism. The mechanism further cornprises' a release magnet253 which, when energized, permits the wiper carriage structure to be returned to rotary and vertical normal; three sets of off-normal springs 254, 25-5 and 256 which are operated when the wiper carriage structure is moved to any vertical ofi-normal position, and a set of normal post springs 25"! which are normally engaged and which are moved out of engagement when the wipers ZEI to 254, inclusive, are elevated to a position opposite any odd-numbered level of bank contacts. The operation of the magnets 253, 252 and 253 is controlled by providing in the selector switch i2 a set of control relays which includes a line relay R229, a

hold relay R236, a transferrelay Riel a cut-' through relay R2l0 and a wipe out relay R235. It will be recognized that the two relaysR23t and R240 are of the well-known slow-acting type, and that the wipe out relay R230 is of the conventional slow-to-operate type. The Strowger switching mechanism incorporated in the connector switch 53" includes wipers 399. SM, 3512 and 393 individual to the four banks of the associated contact field, a vertical magnet 39%, a rotary magnet 365, a release magnet 3%,

and vertical ofi-normal springs 391, Thecontrol network of this switch includes a line relay 123%, a pair of slow-acting hold relays Edit and R326, a level test relay R325 having a' low resistance winding, a slow-to-release pulse circuit cutofi through the operation of automatic plural digit.

pulse senders. which are individual to the various floors. One such pulse sender I5 is illustrated in Fig. 5 of the drawings as being associated with the first floor control stations A, B, etc. Briefly described, this sender comprises a pair of rotary switches 56!] and 570, and a plurality of control relays R5llll, R505, R5l0. R515, R525, R525. R539. Rh tt, R550, R555 and R580. Of the enumerated relays, it will be recognized that the relays R595, R5!!! and R535 are of the well-known slow-tooperatetype, the relay R515 is of the conventional double-wound, two-step type, the relay R528 is of the well-known slow-actingtype, and

the relay R580 is of the slow-to-release type;

The rotary switch 510 includes a single set of contacts having eleven points, a contact wiper I 5'l'l, and an operating magnet 512 for driving this wiper over the contacts of the associated contact set. The rotary switch 535, on the other hand, comprises two banks of contacts, each inand 552 individual to the contact. banks, and an operating magnet 563 for driving the two wipers 5M and 552 over the contactsof their associated contact banks, v

For thepurpose of oper'atively associating the pulse sender I5 with the. pulsing circuits extendingto a selected set of indicators, and the additional purpose of controlling the pilot lamps H35 provided at the first floor control stations A, B,

etc., a relay network l5 individual to the first To this end, the private branch exchange switchboard it! of the hospital is equipped with marking keys [a l 15c, etc., which are individual to the. doctors whose names are posted on the display boards. These keys control marking paths which extend to the. outlet contacts of the various connector switchesso that flashing signals may be produced by the lamps I85, for example, when a doctor who is wanted at theswitchboard dials his identification number at one of the first floor stations A, B, etc. The intermittent energization of the signal; lamps is controlled through the provision of a pulse generator, schematically indicated at 325, which. operates intermittently to connect the pulsing lead. 326 to ground Preferably, the pulse generator 325- is constructed to transmit ground pulses over the lead 326 .at

a rate of one hundred and twenty minute. I

Current for energizing the indicator operating magncta. the control relays, thepilot lamps, the operating magnets: of the rotary, switches, and the operatingmagnets of the Strowger switching mechanisms is supplied from a common direct current source, the positive terminal of. which is pulsesper connected to a commonbus conductor and to, I

ground. The negativeterminal of'the source is connected to a common negative bus conductor which terminates the various relay, magnet and lamp terminals identified. in the drawings by the negative polarity sign. For. convenience in describing the circuits involvecL'this source of current, which may conventionally comprise a storage battery floated across the terminals. of a charging rectifier; has not been shown.

Inconsiclering the operation of, the system, it

' merit." Assuming that the station A is selected for this purpose, the. doctor, before starting the dialing operation, actuates. the connect key tilde. toits off-normal position, thereby to complete a circuit including the contacts H3 and, H5, andthe pulsing contacts 102: of the transmitting decluding twenty-five contact points, wipers 56! vice Ha, for energizing the line relay conventionally embodied in the line switch H. When a loop circuit is thus completed between the station A and the line switch II, this line switch operates in a well-known manner to extend the loop circuit to an idle one of the selector switches. Assuming that the selector switch I2 is. the first idle selector switch available, the wipers of the line switch H are either plunged or rotated to engage the contacts terminating the conductors of the trunk H, in response to the operation of the line relay embodied in the line switch. After the trunk I! is thus selected, the calling loop circuit is extended to include the windings of the line relay R220. As thus extended, this circuit may be traced as extending from ground by way of the upper winding of R220, the contacts 2! i, the conductor Ila, the positive wiper of the line switch II, the contacts H3, the left contacts of the key IMa, the pulsing springs I92, the right contacts of the key lfl la, the contacts N5, the negative wiper of the line switch I I, the conductor ill), the contacts H3, and the lower winding of R220 to battery. Upon operating, the relay R220 closes its contacts 221 to complete a circuit including the contacts 2l8 for energizing the slow-acting hold relay R230. The relay R238 now operates and closes its contacts 23H to complete an obvious path for impressing ground potential upon the release conductor llc. thereby to mark the selector switch l2 'as busy in the outlet contacts of the various line switches, and to provide a holding circuit for the operated cutoff relay conventionally embodied in the line switch ll. At its contacts 23l, the relay R232 also completes a circuit, including the engaged off-normal springs 256, for energizing the upper winding of the slow-acting transfer relay R242. At its contacts 232, the relay R239 prepares a circuit for energizing the upper winding of the relay R2lfi. At its contacts 233, the relay R238 completes a circuit including the resistor 25% for energizing the lower or priming winding of the cut-through relay R2 I I]. The energization of the relay R2l0 over thelast-mentioned circuit is insufiicient to cause the operation of this relay, but serves to render the relay exceedingly fast to operate when its upper winding is subsequently energized. At its contacts 235, the relay R236 opens a point in the operating circuit for the release magnet 253. At its contacts 234, the relay R230 prepares a circuit for energizing the vertical magnet 252 in parallel with the lower winding of the transfer relay R240. The transfer relay R240, upon operating, opens its contacts 2 to prevent current pulses from being delivered to the rotary magnet 250 during the dialing of the first digit at the calling control station A. At its contacts 222, the relay R240 further prepares the above-mentioned circuit for energizing its lower winding in parallel with the vertical magnet 252. At its contacts 243, the relay R24 opens another point in the operating circuit for the release magnet 253. Following the operation of the transfer relay R240 to perform the functions just described, the selector switch l2 is conditioned to respond to the impulses of the first digit dialed at the station A.

When the first digit 1 is dialed at the statlon A, the pulsing springs I82 are opened and closed to transmit an impulse over the above-traced loop circuit to the line relay R220. This relay, upon restoring at the beginning of the open-circuit period of the impulse, opens it contacts 22| to interrupt the operating circuit for the hold relay R232, and closes its contacts 222 to complete the prepared circuit for energizing the vertical magnet 252 in parallel with the lower Winding of the transfer relay R248. The latter circuit extends from ground by way of the contacts 2E8, 222, 234 and 222, and the parallel-connected windings of the relay R240 and the vertical magnet 252 to battery. When energized over this circuit, the vertical magnet 252, operating in conjunction with its associated ratchet and pawl mechanism, functions to actuate the wipers 26! to 264, inclusive, one step in the vertical direction to a position opposite the first level of contacts in the associated contact field. When the wipers of the selector switch 12 are thus elevated to a position opposite an odd-numbered level of bank contacts the normal post springs 25! are disengaged to interrupt thepath normally shortcircuiting the lower oroperating winding of the wipe out relay R226. Incident to this movement of the wiper carriage structure the vertical offnormal springs 252 are moved into engagement to prepare the operating circuit for the rotary magnet 256; the vertica1 off-normal springs 255 are engaged to prepare the operating circuit for the release magnet 253; and the vertical off-normal springs 255 are disengaged to deenergize the upper wind-ling of the transfer relay R240. The purpose c-f energizing the lower winding of this transfer relay in parallel with the winding of the vertical magnet 252, during the dialing of the first digit, now becomes apparent. Thus this parallel circuit provides a vehicle whereb the transfer relay is intermittently energized and thereby maintained in its operated position throughout the series of impulses transmitted to the selector switch l2. In this regard, it will be understood that a first digit comprising any number of impulses from one to-ten may be dialed at a calling control station from which the selector switch !2 is seized. Due to the slow-to-release characteristics thereof, the relays R230 and R250 remain operated during the operation of the line relay R229 to repeat the dialed impulse or impulses to the vertical magnet 252.

Shortly following the end of the first digit, the transfer relay R260 restores. In releasing, this relay opens its contacts 242 to prevent further impulses from being transmitted to its lower winding and the winding of the vertical magnet 252 in parallel, and closes its contacts 243 further to prepare the operating circuit for the release magnet 253. At its contacts 2M, the relay R248 completes a circuit for energizing the rotary magnet 256, this circuit extending from ground by way of the contacts 2i8, 22l and 24!, the offnormal springs 254, the contacts 25!, and the winding of the rotary magnet 25!] to battery. When thus energized, the magnet 25!] operating in conjunction with its associated ratchet and pawl mechanism functions to rotate the wipers 26! to 264, inclusive, into engagement with the contacts forming the first contact set of the selected level. At its contacts 25!, the magnet 250 opens its own operating circuit. Further operation of the magnet 250 depends upon the idle or busy condition of the first trunk in the selected group, i. e. the trunk terminated at the first set of contacts in the selected level and extending to the first connector switch of the selected group. If this trunk is busy, the private conductor thereof is marked with ground potential and, accordingly, the upper winding of the cut-through relay RZIU is short-circuited over a path which extends by way of the grounded wiper 253, the contacts 232,

the upper winding of R210 and the contacts 231 back to ground. On the other hand, if the first trunk of the group is idle the private, conductor thereof is marked with negative battery potential, so that a circuit is completed for energizing the upper Winding of the cut-through relay R210. Assuming that the first trunk is busy, the magnet 252 restores and closes its contacts 251 to recomplete its operating circuit. When this circuit is recompleted the magnet 250 reoperate andadvances the wipers 261 to 2154, inclusive, a second step wherein the engage the contacts terminating the conductors of the trunk extending to the second connector switch of the selected group. If this connector switch is also busy the magnet 250 advances the wipers 261 to 204, inclusive, a third step, thereby to select the third switch of the group. This stepping operation on the part of the selector switch wipers 261 to 260, inclusive,

continues until an idle connector switch of the group is found. Assuming that the connector switch 13 is the first idle switch in the group, the rotary movement of the wipers 201 to 264, inclusive, is arrested when these wipers are positioned to engage the contacts terminating the conductors of the trunk 18. Thus when the wiper 20,3 engages the contact terminating the conductor 180, the upper or operating winding of the cutthrough relay R210 is energized in a circuit which extends from ground by way of the contacts 231, the upper winding of R210, the contacts'2'32, the wiper 263, the conductor 180, the contacts 314, and the resistor 31.7 to battery. Immediately this circuit is established, the relay R210 operates and opens its contacts 218 to interrupt the abovetraced operating circuit for the rotary magnet 250. Thus further rotary movement of the wipers 201 to 200, inclusive, is prevented. At its contests 218, the relay R2 i also opens a point in the 1 operating circuit for the release magnet 253. At

its contact 216, the rela R210 completes acircuit for energizing its middle and lower windings in series, this circuit extending from ground by way of the contacts 231 and 216, and the seriesconnected middle and lower windings of R2 to battery. At its contacts 215, the relay R210 completes an obvious path for short-circuiting its upper winding. Incident to the closure of the con- 1 tacts 215 a path, including the contacts 231 and the wiper 263, is completed for impressing ground potential upon the release conductor 180 of the n trunk l8, thereby to mark the connector switch i3 against seizure by another of the selector switches. At its contacts 21''], the relay R210 prepares a circuit for energizing the relays R1 10,

R520 and R200, and the pilot lamp 105. At its contacts 212 and 214, the relay R210 extends the calling loop circuit to include the wipers 261 and 202', the trunk conductors 18a and 18b, and the two windings of the line relay R300. At its contacts 211 and 213, the relay R210 excludes the windings of the line relay R220 from the calling a point in the circuit for transmitting current pulses to the magnets 300, 304 and 305 and the pulsing leads associated with the wipers 3! and 332. The hold relay R310, in operating, closes its contacts 311 to prepare the pulsing circuits just mentioned and to prepare locking oircuitsfQRthe control station A is operativcly associated with transfer relays R340, R350, R310 andR380, At its contacts 312, the relay R310 prepares the operating circuit for the transfer control relay R320. At its contacts 314, the relay R310 opens the path over which negative battery potential is normally impressed upon the release conductor 10c. At its contacts 313, the relay R310 conmeets the release conductor E30 to ground,,thereby to complete a multiple locking circuit for, the cut-through relay R210 and the operatedcut-oii relay of the line switch 11. At itsv contacts M0, the relay R310 prepares a locking circuit for the relay R330 and the common portion of the operating circuits for the relay R330, R300, R350,

R310 and R330. At its contacts 356, the relay R350 opens a point in the operating circuit for the release magnet 300.

As explained above, incident to the operation of the cut-through relay R210, the relay R220 restores to open the'operating circuit for thehold relay R230 and to prepare the operating circuit for the release magnet 253. Due to the slow-torelease characteristic, the, relay R230 remains operated until the hold relay R3! oi the connector switch 13 operates. Thereafter the relay R230 restores and opens its contacts 231 tointerrupt the initially completed path for impressing ground potential upon the release conductor I'Ec, whereby the operating and locking circuits for the relay R210 and the initially completed locking circuit for the cut-oil relay of the-line switch 11 are opened. At its contacts 232, the

.relay R230 opens another point inthe operating circuit for the relay R210. At its contactsiltii, the relay R230 opens the initially completed circuit for energizing the lower winding of the relay R210. Atits contacts 235, the relay R230 further prepares the operatingcircuit for the release magnet 253. Following the operations'just described, the calling device 101a provided at the the linerelay R300 of the connector switch 13,

and this connector switch is conditioned torespond to the impulses of the second digit of the identification number 105 assignedto the calling doctor.

When the second digit 6f of the doctors identification'number is dialed a t the station A,

the pulsing springs H32 are opened and closed six times so that six impulses are transmitted to the relay R300. 'This relay functions; to repeat the pulses to the transfer. control relay R32land the vertical magnet 304. Thuseach timerthe relay R300 restores, it. closes its contacts 303 toenergize the relay R320over anobvious circuit.

At its contacts 3fl2,-the relay R300 opens the circult for energizing the hold relay R320. At its contacts 301, the relay R300 completes a circui t including the contact 3 1i and 382 for energizing theverticalmagnet 300. From the above explanation, it will be understood that the relay R320 operates at'the beginning of the open-circuit period of the first impulse transmitted to the relay R300. Due to its slowto'release characteristic, this relay remains operated, until shortly after the train of six impulses is ended. Similarly, the slow-acting hold relay R3'l'0 does not restore in response'to the intermittent-deenergizationof its winding.

relay R320 closes its contacts 321 to complete a In operating, the

circuit for energizing the lower winding of the transfer relay R380, this circuit extending from ground by way of the contacts 3E5, 322i and 305, and the lower winding of R380 tobattery; W'hen its lower winding isgthus; energized, the relay R380 only partially operates to close its preliminary make contacts 303. At these contacts a path is completed for short-circuiting the upper winding of the relay R380, this path extending from ground by way of the contacts 3E5, 32I and 385, the upper winding of R380 and the contacts 383 and 3 back to ground.

Each time the vertical magnet 30 i is energized in the above-traced pulsing circuit it operates in conjunction with its associated ratchet and pawl mechanism to elevate the wiper carriage structure one step, so that at the end of the second digit dialed at the calling station A the wipers 330 to 392, inclusive, are left standing opposite the sixth level of bank contacts. Incident to the first vertical step of the wiper carriage structure, the off-normal springs 391 are moved into en gagement to prepare the operating circuit for the release magnet 335. Shortly following the end of the second digit, and during the inter-digit pause between this digit and the third'or final digit, the transfer control relay R320 restores.

In releasing, this relay opens its contacts 321 to interrupt the above-traced path short-circuiting the upper winding of the transfer relay R385. When this path is opened, the two windings of the relay R300 are energized in series over a circuit which includes the contacts 383 and 3! I. The relay R380 now completes its operation, and in so doing opens its contacts 385 to interrupt its operating circuit as traced above. At its contacts 384, the relay R380 prepares a circuit for'energizing the lower winding of the transfer relay R310. At its contacts 33L the relay R380 prepares a circuit for energizing the rotary magnet 305. At its contacts 302, the relay R300 opens another point in the above-traced circuit for transmitting current pulses to the vertical magnet 394. I

When the third digit 5 of the doctors identification number is dialed at the stationA, the pulsing springs I02 are opened and closed five timesso that five impulses are transmitted to the relay R300. This relay, in following the impulses, functions to transmit a corresponding number of current pulses to the transfer control relay R330 and the rotary magnet 395. The circuit for energizing the rotary magnet 395 may now be traced as extending from ground by way of the contacts 3I'I, 30I, 38I and 312, and the winding of the magnet 305 to battery. Upon reoperating at the beginning of the third digit, the relay R320 closes its contacts 32I to complete the prepared circuit for energizing the lower winding of the transfer relay R310, this circuit extending from ground by way of the contacts 3I5, 32I, 384 and 315, and the lower winding of R310 to battery. When its lower winding is thus energized, the relay R310 only partially operates to close-its preliminary makecontacts 313. At these contacts a path is completed for short-circuiting the upper winding of the relayR310, this path extending from ground by way of the contacts 3I5, 32I, 384'and 315, the upper winding of R310, and the contacts 313 and 3H back to ground.

Each time the rotary magnet is energized in the above-traced pulsing circuit it operates, in conjunction with its associated ratchet and pawl mechanism, to rotate the wiper carriage structure one step, so that at the end of the third digit the wipers 390 to 333, inclusive, are left standing in engagement with the fifth contacts of the sixth level in the associated contact bank.

In this position of the wiper carriage structure, the indicated wipers respectively engage the contacts I65a, I651), I650 and I55d. At the end of the third digit dialed at the calling station A, the relay R300 remains in its operated position so that the transfer control relay R320 and the rotary magnet 305 are deenergized. Shortly after the digit is ended, the relay l 320 restores and opens its contacts 32I to interrupt the path short-circuiting the upper winding of the relay R310. When this path is opened the two windings of the relay R310 are energized in series over a circuit which includes the contacts 313 and St I. The relay R310 now completes its operation, and in so doing opens its contacts 315 further to interrupt its own operating circuit. At its contacts 314, the relay R310 prepares a circuit for energizing the lower winding of the transfer relay R350. At its contacts 31I, the relay R310 prepares a circuit for energizing the restoring relay R610 of the selected display unit 2 6 and the parallel-connected restoring relays of the corresponding display units provided on the other display boards. At its contacts 312, the relay R310 opens the above-traced circuit for transmitting current pulses to the rotary magnet 395. At its contacts 311, the relay R310 prepares the operating circuit for the signal con trol relay R380. At its contacts 315, the relay R310 completes the prepared circuit for energizing the lower winding of the transfer relay RI I0 in series with the lower winding of the wipe out relay R280, and the lower winding of the reset pulse cut-ofi relay RI20. This circuit extends from ground by way of the contacts 36I and 316, the conductor I89, the wiper 264, the contacts 2I1, the lower winding of R200, the conductor He, the control path through the line switch II, the contacts I35 and I18, the lower winding of RI i0, and the lower winding of RI20 to battery. Due to the resistance of the lower winding of the relay R200, the current traversover a pathincluding its preliminary make contacts I5 and the contacts I 32. At its contacts IIB, the relay RIII] opens the above-traced series-operating circuit. At its contacts II1, the

relay RI I0 completes a circuit for energizing the parallel-connected pilot lamps I05 in series with the lower winding of the wipe out relay R200. This circuit extends from ground by way of the contacts 36I and 316, the conductor I8e, the wiper 264, the contacts 2| 1, the lower winding of R200, the conductor I16, the control path through the line switch II, the contacts I35 and H1 and the parallel-connected lamps I05 to battery. The energization of these lamps serves to provide an indication that the relay and pulse sending equipment individual to the first floor stations is busy. When its lower winding is energized, first in series with .the windings of the relays RI i0 and RI20 and later in series with the parallel-connected pilot lamps I05, the wipe out relay R200 operates and locks to the grounded release conductor I10 over a path including its preliminary make'contacts 20L After this path is completed the relay R200 closes its contacts 202 to short-circuit its lower winding and thus increase the energization of the pilot lamps I05. I

The transfer relay RI I0, upon operating, also closes its contacts l l2 and IM to complete an alternative loop circuit which extends from the pulse sender 5 to the windings of the line relay R380 in the operated connector switch 13. This loop circuit may be traced as extending from ground by way of the upper winding of R360, the conductor l8a,the wiper 23.1, the contacts N2, the conductor Ila, the positive wiper of the line switch H, the contacts H2, 5 12, .528, 544 and N4, the negative wiper of the line switch ll, the conductor ill), the contacts 2M, the wiper 252, the conductor I81), and the lower winding of RSM to battery. After this circuit is completed, the relay R! it opens its contacts H3 and M5 to exclude the pulsing springs N2 of the transmitting device Hlla from the loop circuit. At its contacts ill, the relay Rim completes an obvious circuit for energizing the start relay R563 of the pulse sender ES. From the above explanation, it will be understood that'after the transfer relay RI H3 operates, the control of the switching equipment is transferred from the calling control station A to the pulse sender 15. It will further be apparent that no additional operations are required on the part of the calling this regard, it will be noted that the pilot lamps Hi5 individual to the first floor stations are held energized to indicate the busy condition of the relay network It and the pulse sender l5, until the operated switching equipment is released.

The pulse sender l5 first operates to transmit ten restoring pulses to the line relay R380 of the operated connector switch 53. Thus, when. the start relay Halli": operates, it closes its contacts 562 to complete a circuit including the contacts 5% and 59? for energizing the upper winding of the relay R5535 in parallel with the operating magnet 512 of the rotary switch 570. At its contacts till, the relay R563 prepares a circuit for energizing the upper winding of the relay R5l5. At its contacts 533, the relay Refill prepares a circuit for energizing the upper winding of the relay R539 in parallel with the operating magnet 563 of the rotary switch 56%). When the magnet 572 is thus energized it opens its contacts 573 to interrupt the prepared operating circuit for the pulsing relay R525, and conditions its associated ratchet and pawl mechanism to step the wiper 512! into engagement with its associated second contact. Shortly after the magnet 512 is energized, the slow-to-operate relay R505 operates and locks to ground over a circuit including its preliminary make contacts Eilt and the. contacts lil. After this loclaingcircuit is completed, the relay 35d? opens its contacts 501 to interrupt its operating circuit as traced above. Atits contacts 586, the relay R585 opens the circuit for energizing the magnet 532. When this magnet is thus deenergized its associated operating pawl is retracted to advance the wiper 57H one step. At

battery. When thus energized, the relay R525 closes its contacts 52'! to energize the slow-acting relayrRSZil. At its contacts {526, the relay R525 completes an .obvious circuit for again energizing the magnet 52 2. The relay R520, upon operating,

relay R525, in restoring, opens its contacts 525 to deenergize the magnet 512. ,Since the second to eleventh contacts or" the contact set associated with the wiper Eli are multipled together and connected togrouhd, the interrelated operation vofthe pulsing relay, R525 continues until the lower end of the double-ended wiper 57! is operated to engage the first contact of the associated contact bank, at which time theoperating circuit iior the pulsing relay R525 is obviously opened-to prevent further operation of this relay and the magnet 5%. As indicated by the foregoing explanation, a current pulse is transmitted to the relay R528 each time the pulsing relay R525 operates. Due to ltSSlOWr-tO-IBIGELSB characteristic, the relay RdZil remains operated throughout the described cycle of operation of the rotary switch 579.

Y Incident to the operation of the switch 570, ten

restoring pulses are transmitted to the operating magnets Fla and lillb of the indicators 400a and Gilfilb and to the operating magnets of the corresponding indicators of the other display boards. Thus each time the pulsing relay R525 operates, it opens the above-traced loop circuit extending, through the windings of the relay R389. It will be understood, therefore, that the relay R368 follows the impulses and functions to repeat the same over the restoring pulse circuit extending tothe selected indicators. When the relay Rttll first restores at the beginning of the restoring pulse train, it closes its contacts 303 to again energize the transfer control relay R320.

This relay now operates and remains in its operated position until shortly after the impulse train ends. In reoperating, the relay R328 closes its contacts 32% to complete a circuit including the contacts M5, 33 i, 314 and 355 for energizing the lower winding of the transfer relay R350. The relay R356 now partially operates to close only its preliminary make contacts 353'. At these contacts, a path is completed for short-circuiting the upper winding of the relay R358, this path extending from ground by way of the contacts 3 and 353, the upper winding of R350, and the contacts 355, 374, 3%, 32! and M5 back to ground.

The ten restoring pulses are repeated by the relay PAWS to the restoring relay R480 of the display unit '26 over a circuit which extends from ground by way of the contacts 3! l, 31', 33B, 38!, t'll' and 352, the restoring pulse lead, the wiper tilt and its engaged contactj lfific, and the winding of RM?! to battery. "Branches of this circuit extend to the restoring relays respectivelyembodied in'the display units that correspond to the unit it and are provided on the other display boards. Each time the restoring relay R410 opermutating springs 502 are engaged. Accordingly,

if the indicating drum of the register 4000., for example, is assumed to occupy its second 01T- normal position at the time the operation of the restoring relay Rdli] is initiated, nine of the ten restoring pulses willbe transmitted to the magnet ltla. Each time this magnet is energized the indicating drum of the register 400a is advanced one step nearer its normal or blank position. At the end of the ninth step, the cam 403a.

operates to open the commutating contacts 502a,

thereby to prevent the remaining restoring pulse of the train from producing further operation of the magnet 40Ia. In a manner similar to that just described, a portion or all of the restoring pulses transmitted by the relay R4 I to the magnet Ib may be utilized for the purpose of driving the indicator drum of the register 4002; back to its normal or blank position. Thus if the indicating drum of the register 400 occupies its fifth off-normal position, for example, at the time operation of the relay R4I0 is initiated, six of the restoring pulses will be utilized to advance this drum to its normal or blank position. It will be understood, from the above explanation, that after a maximum of ten restoring pulses have been transmitted through operation of the relay R300 to the restoring relays of the selected display units, all of the indicator drums of the indicators in these units are restored to their normal or blank positions.

After the train of ten restoring pulses has been counted through operation of the rotary switch 510, the relay R525 remains in its restored position and the relay R520 is deenergized and re stores. In releasing, the relay R520 closes its contacts 522 to prepare the operating circuit for the slow-tc-operate relay R5l0. At its contacts 52I, the relay R520 interrupts the path shortcircuiting the lower winding of the relay R5I5, permitting the two windings of the latter relay to be energized in series over a circuit which includes the contacts 5I6 and I I I. The relay R5I5 now completes its operation, and in so doing closes its contacts 5I'l to energize the relay R5I0 in a circuit which includes the contacts 522 and III. At its contacts 5i0, the relay R5I5 completes a circuit for energizing the lower winding of the transfer relay RI50, this circuit extending from ground by way of the contacts 5I8, 5! I, I23, I33 and I54, and the lower winding of Rl to battery. When its lower winding is thus energized, the relay RI partially operates to close only its preliminary make contacts I52, At these contacts, a path including the additional contacts I3I, I54, I33, I23, 5H and 5I8 is completed for short-circuiting the upper winding of the relay RI50. Shortly after the relay RI 50 partially operates, the relay R5I0 operates and opens its contacts to interrupt the short-circuiting path just traced. When this path is opened, the two windings of the relay RI 50 are energized in series over a circuit which includes the contacts I3.I and I52. The relay RI 50 now fully operates, and in so V doing opens its contacts I54 further to interrupt its operating circuit, At its contacts I53, the relay RI50 prepares the operating circuit for the relay RI40. At its contacts I5I, the relay RI50 completes an obvious circuit for energizing the transfer relay R500.

The relay R540, in operating, closes its contacts 54I and 543 to include the contacts 555 of the pulsing relay R555 in the loop circuit extending to the windings of the line relay R300. Thereafter the relay R540 opens its contacts 542 and 544 to exclude the contacts 528 of the pulsing relay R525 from the established loop circuit. Thus, control of the relay R300 is transferred from the pulsing relay R525 to the pulsing relay R555. At its contacts 545, the relay R540 completes a circuit for energizing the operating magnet 553 of the rotary switch 560, this circuit extending from ground by way of the contacts 503, 545 and MI, and the winding of the magnet 563 to battery. When thus energized, the magnet 553 opens its contacts 584 to interrupt the incomplete operating circuit for the stepping relay R550, and conditions its associated ratchet and pawl mechanism to step the wipers 56I and 552 from their illustrated normal position into engagement with their respective associated second contacts. In operating, the transfer relay R540 also completes a circuit including the contacts 503, 545 and 532 for energizing the upper winding of the slow-to-operate start cut-off relay R530. The relay R530, in operating, locks to ground over a path including the contacts 533 and I I I. After this locking circuit is completed, the relay R530 opens its contacts 532 to interrupt its operating circuit. At its contacts 53I, the relay R530 opens the operating circuit for the magnet 583. When thus deenergized, the magnet 553 retracts its associated operating pawl to advance the wipers 56I and 552 into engagement with their respective associated second contacts. At its contacts 554, the magnet 5B3 completes the prepared operating circuit for the stepping relay R550, this circuit extending from ground by way of the wiper 562 and its engaged second contact, the contacts 564 and the winding of R550 to battery. When thus energized, the relay R550 closes its contacts 552 to again energize the magnet 563. The magnet 563 now reoperates, and opens its contacts 564 to deenergize the stepping relay R550. The relay R550, in restoring, opens its contacts 552 to deenergize the magnet 553. Since the second to twenty-fifth contacts of the contact set associated with the wiper 562 are connected to ground, the interrelated operation of the stepping relay R550 and the magnet 563 continues until the lower ends of the double-ended wipers 56I and 552 are operated to engage the respective first contacts of the associated contact banks. When this occurs the operating circuit for the stepping relay R555 is obviously opened to prevent further operation of this relay and the magnet 563.

Immediately after the train of ten restoring pulses is transmitted over the restoring pulse lead and the wiper 392 to the restoring relays of the selected display units, and before the stepping operation of the rotary switch 550 is initiated in the manner explained above, the transfer relays of the connector switch I3 operate to transfer the pulsing circuit from the restoring relays to the operating magnets of the tens indicators in the selected display units. Thus when the relay R320 restores shortly after the end of the restoring pulse train, the path short-circuiting the upper winding of the transfer relay R350 is opened at the contacts 32I. When this path is opened the two windings of the relay R350 are energized in series over a circuit which includes the contacts 3H and 353. The relay R350 now completes its operation, and in so doing opens its contacts 355 furthertointerrupt its operating circuit. At its contacts 355, the relay R350 prepares the operating circuit for the transfer relay R3 55. At its contacts 35E, the relay R353 prepares a circuit for transmitting reset pulses over the first digit reset pulse. lead totheoperatingrnagnets of the tens indicators in each of the selected display units. At its contacts 352, the relayv R353 opens the above-traced circuit traversed by the restoring pulses. I i i After the transfer relaysRl53 and R35ii operate, and during the operation of the rotary switch 533, ten reset pulses are transmitted to the tens indicator 333a oi": the display unit 26 and to the tens indicators of the corresponding display units in the other display boards. Thus each time the stepping relay R553 operates to energize the magnet 553 of the rotary switch 569, it closes its contacts 55l to complete a circuit extending through the wiper 55! for energizing the pulsing relay this .circuit also including the multipled second to eleventh contacts of the contact set associated with the wiper 535. Each time the pulsing relay R555 operates it opens its contacts 553 to interrupt the loop circuit extending through the windings of the line relay R336. Thus the relay R363 is caused to follow the impulses, and functions to repeat the impulses to the operating magnet/tiller of the tens indicator 433a. The circuit over which these impulses are transmitted to this magnet extends from ground by way of the contacts 3H, 33!, 336,38l, 3H, 35I and 332, the first digit reset pulse lead, the wiper 33! and its engagedcontact I352), and the winding of the magnet 4531a to battery. Correspending parallel circuits are completed forenergzingthe operating magnets of the tens indicators of the other selected display units. Each time the magnet lflla is energized and deepergized, the display drum of the indicator 433a is advanced one step, so that after the ten reset pulses of the first digit are counted through operation of the rotaryswitch 53%, this display drum is positioned to display the numeral 03 During the transmission of the first digit of reset pulses in the manner just explained, the relay RBZE] is operated to complete a circuit for energizing the transfer relay R359, thiscircuit extending from ground by way of the contacts 35 5, SH, .38 4, 31 i, 354 and 355, and the lower windng of R355 to battery. Whenenergized over this circuit at the beginning of the digit, the relay R335 partiallyoperates and closes only its preliminary make. contacts 353 to complete a path for'sho-rt-circuiting its. upper winding, this path extending from ground by way of the contacts 3i i and 333, the upper winding of R353, and the contacts 345, 35 3%, 38d, 32I and 395 .back to ground.

After the ten reset pulses of the first reset digit are counted by the rotary switch 553, the wipers of this switch are operated successively to err-- gage their respective associated twelfth, thi teenth and fourteenth contacts. During such movement of the wipers 5M and 552 the circuit for energizing the pulsing relay R555 is held open. Accordingly, the relay R555 remains in its restored position and the relay R393 holds its operated position for a measured time interval wh ch comprises an inter-digit pause between the two reset pulse digits. During this interval and when the wiper 53! is steppedto engage its asthe selected display units.

sociated thirteenth contact, the circuit for energizing the transfer relay RI 40 is further prepared. This circuit is completed at the contacts 55I when the stepping relay R550 next operates, and extends from ground by way of the contacts 55 I, the wiper, 55I and its engaged thirteenth contact, the contacts I23, E33, I53 and I43, and the lower winding of RMS to battery. When its. lower winding is thus energized, the relay RI 4E3 partially operates to short-circuit its upper winding over a path including the contacts I3I, IdI, I43, I53, I33, I23 and I5I, and the wiper 53!. When the wiper 53I is thereafter stepped out of engagement with its associated thirteenth contact, this short-circuiting path is broken, permittingthe two windings of the transfer relay Rl lfl to be energized in series over a circuit which includes the contactslsl and MI. The relay RIM now completes its operation, and in so doing opens its contacts I43 furthertointerrupt its operating circuit as traced above. At itscontacts I42, the relay RI 40 prepares the operating circuit for the release relay Rl3il.

During the inter-digit pause measured by the rotary switch 550 between the two reset pulse digits, the relay R320 restores and opens its contacts 32I to interrupt the path short-circuiting the upper winding of the transfer relay R340. The two windings of the latter relay are now energized in series over a circuit including the contacts 3H and 343. When its two windingsare thus energized, the relay R3 i3completes its operation, and in so doing opens its contacts 345 further to interrupt its operating circuit as traced above. At its contacts 354, the relay R3 55 pre pares the operating circuit for the relay R333. At itscontacts 3M, the relay R3 55 prepares a circuit for transmitting the pulses of the second r eset pulse digit to the operating magnet of the units indicator 53Gb andthe 'units indicators of the correspondingdisplay units of the other display boards. At its contacts 342, the relay R330 opens the above-traced circuit over which the pulses of the first reset digit were transmitted to the operated magnets of the tens indicators in Following the operations just described, and during continued movement of the rotary switch 563, the single impulse of the second reset pulse digit is transmitted to the operating magnets of the unitsindicators inthe selected display units. Thus during the period when thewipers 55Iand 562 engage their associated fifteenth contacts,

"the stepping relayR55ll again closes theoper ating circuit for the pulsing relay R555 so that an impulse is transmitted to the relay R330. The relay R303, in restoring and reoperating, closes its contacts 363 momentarily to complete the operating circuit for the transfer controlrelay R320. At its contacts 3M, the relay R3011 trans mits a current pulse to the operating'magliet 48H) of the units indicator 4352) over a circuit which extends from ground by way'of the contacts 3H, 311L336, 3BI,'3lI, 35I, 3M endear, the second digit reset'p'ulse lead, the wiper 3'90 and its engaged contacts Id,and the winding of the magnet 40 It) to battery. Branches of this circuitextend through the windings of the operating magnets of the other units indicators in the selected display units. The relay R320, upon reoperating, closes its contacts 32I to complete the prepared circuit for energizing thelower winding of "the transfer relay R335, this circuit extending from ground by way of the contacts 3I5, 32I,'38 4, 314, 354,344 3116:1333, and the lower winding of R330 to battery. When its lower winding is thus energized, the relay R330 partially operates to close only its preliminary make contacts 332, and thus complete a path including these contacts and the contacts 32!, 380, 314, 354, 344 and 333, for short-circuit'ing its upper winding. When the operating magnets of the units indicators in the selected display units are energized over the circuit traced above, the associated display drums are advanced one step wherein each drum' is positioned to display the numeral "1 through its associated display window.

Following the operations just described, the indicators 400a and 400?) are reset to display the number 01 which indicates that the corresponding doctor No. 165 may be located on the first floor of the hospital. In this regard, it will be noted that the second reset pulse digit comprises only a single reset pulse. It is to this end that the fifteenth to the twenty-third contacts of the contact set associated with the wiper 56! are not wired. Accordingly, when this wiper is moved out of engagement with its associated fifteenth contact, no further circuit is available for transmitting pulses to the pulsing relay R555. It will be noted, however, that the wiring of the contact set associated with the wiper 56! in the pulse sender individual to each floor determines the number of reset pulses which are transmitted during each cycle of operation thereof. Thus, had the pulse sender I5 been provided on the twenty-fifth floor, for example, only the second. third and fifteenth to nineteenth contacts of the contact set associated with the wiper 53! would have been multipled together to provide a circuit for transmitting a first reset digit of two pulses and a second reset digit of five pulses. It will thus be apparent that by varying the wiring of the contact set associated with the wiper 56! the pulse sender I5 may be adapted to transmit first and second rest pulse digits comprising any desired number of pulses.

At the end of the second reset digit, the relay R300 remains in its operated position. Accordingly, the transfer control relay R320 is deenergized and restores. In releasing, this relay opens its contacts 32! to interrupt the path short-circuiting the upper winding of the transfer relay R330. The two windings of the transfer relay R330 are now energized in series over a circuit which extends from ground by way of the contacts 3I5 and 332, the upper winding of R330 and the lower winding of R330 to battery. When this circuit is completed the relay R330 com letes s operation. At its contacts 33!, the relay R330 cuts off the pulsing circu t so that further operation of the line relay R300 is of no effect. At its contacts 333, the relay R330 opens a point in i s o erating circuit as traced above, thus rendering the relay R330 inoperative to effect further control of the five transfer relays.

After the selected indicators are reset in. the manner explained above, and during continued operation of the rotary switch 560. the wipers and 562 are positioned to en ag thei associated twenty-fourth and twenty-fifth contacts. Dur ing this period the relay R520 twice operates to complete an obvious circuit for energizing the slow-to-release relay R580, Followin the operation of the relay R500. the wipers 56! and 582 of the rotary switch 560 are returned to normal and the operation of this switch is arrested in the manner explained above. When the wiper 56! is moved to disengage its associated twenty-fifth contact, the circuit for energizing the relayR580 is broken. During the period when the relay R580 is operated, a circuit including the contacts 58!, I23, I33, I53 and I42 is completed for energizing the release relay RI30. In operating, the relay RI30 first locks to ground over a path including its preliminary make contacts I 34 and the contacts 58!. After this locking circuit is completed, the relay RI30 opens its contacts I33 to interrupt the operating circuits for itself and the two transfer relays RI40 and RI50. At its contacts I3! the relay RI30 opens the locking circuits for the relays RI40 and R! 50 to cause the deenergization and release thereof. The relay RI50, upon restoring, opens its contacts I5! to deenergize the transfer relay R540. At its contacts I35, the relay RI30 opens the previously traced circuit for energizing the pilot lamps I05 in parallel, and a point in the previously traced operating circuit for the transfer relay RIIfi. When the pilot lamps I05 are thus deenergized the pulse sender l5 and the relay network I6 are identified as being idle. At its contacts I32, the relay R! 30 opens the locking circuit for the transfer relay RI I0, to cause the deenergization and release of the latter relay.

The relay RI I0, upon restoring, opens its contacts H2 and H4 to interrupt the loop circuit extending to the connector switch I3, and opens its contacts III to deenergize the relays R500, R505, R5I0, R5 I5 and R530 of the pulse sender l5. Shortly after these relays restore, the wipers of the rotary switch 530 are returned to normal, in the manner explained above, to cause the deenergization and release of the relay R580. This relay, in restoring, opens its contacts 58! to interrupt the locking circuit for the relay Rl30. Following the release of the relay RI30, the pulse sender I5 and the relays of the network I6 are fully restored to normal.

When the loop circuit extending to the connector switch I 3 is opened, in the manner pointed out above, the relay R300 is deenergized and restores to recomplete the operating circuit for the relay R320, and to open the operating circuit for the hold relay R3I0. Shortly thereafter, the relay R350 restores and opens its contacts 3I2 to deenergize the relay R320. The momentary operation of the latter relay is without effect. In releasing, the relay R3I0 also opens its contacts 3i! and 315 to cause the deenergization and release of the five transfer relays R330, R300, R350, R370 and R380. At its contacts 3I6, the relay R3Iil completes the prepared operating circuit for the release magnet 396. When this magnet operates, the wiper carriage structure of the Strowger switching mechanism is restored to rotary and vertical normal in a manner well understood in the art. Incident to the restoration of the wipers 390 to 393', inclusive, to their respective normal positions, the vertical offnormal springs 39'! are opened to deenergize the release magnet 395. Following the release of the Strowger switching mechanism the connector switch I3 is fully restored to normal.

Incident to the release of the hold relay R3I0, the contacts 3I3 are disengaged to disconnect the release conductors I and Ho from ground, whereby the cut-through relay R2I0, the wipe out relay R200, and the cut-off relay of the line switch I! are all deenergized and restore. At its contacts 3M, the relay R3I0, in releasing, connects the release conductor IBc through the resistor 3!! to the negative terminal of the current source, whereby the connector switch I3 is marked as idle in the bank contacts of the selec tor switches having access thereto.

When the cut-through relay R2l0 restores, it closes its contacts 2I0 to complete a circuit including the contacts 222, 235 and 203, and the vertical off-normal springs 255 for energizing the release magnet 253. When this magnet is energized, the wipers 20I to 264, inclusive, are restored to their respective normal positions in the usual manner. Incident to release of the wiper carriage structure, the vertical off-normal springs 254 are disengaged further to interrupt the operating circuit for the rotary magnet 250; the vertical off-normal'spiings 255 are disengaged to deenergize the release magnet 253; the vertical off-normal springs 250 are operated into engagement to reprepare the operating circuit for the transfer relay R240; and the normal post springs 251 are moved into engagement to recomplete the path for short-circuiting the lower winding of the wipe out relay R200. Following the operations just described, the selector switch I2 is fully restored to normal and the release conductor He is connected through the upper winding of the transfer relay R240 to the negative terminal of the current source, whereby this switch is marked as idle in the bank contacts of the various line switches. When the cut-off relay embodied in the line switch II restores this switch is released, in a manner well under- 1 stood in the art. Following the release of the line switch II and the selector switch I2, all of the equipment utilized in resetting the selected indicators individual to the doctor No. 165 is fully restored to normal.

From the above explanation it will be apparent that as the doctor No. 165 proceeds from floor to floor, he may, by repeatedlydialing hisidentiiication number at one of the controlstations on each floor, reset the display units assigned for his use to display numbers which accurately indicate his location; If this doctor proceeds to a ward or floor where he will be occupied with duties from which he does not wish to be disturbed, he may wipe out the'indications displayed by the display units provided for his use, without resetting these units to provide a new floor indication. For example, the doctor may be occupied with duties in surgery, in which case he will not wish to be disturbed. In order to wipe out the existing indications displayed the units provided for his use, the doctor No. 165 may dial the number 265 at any one of the control stations provided in the hospital. Assuming that this number is dialed at the control station A, for example, and that the selector and connector switches I2 and I3 are utilized in selecting the display unit and the corresponding display units of the other boards, the wipers of the selector switch I2 are positioned opposite the second level of contacts in the associated contact bank at the end of the first digit. Thus the trunk I8 is seized through the contacts of an even-numbered contact level. Incident to the movement of the wipers ZEI to 254, inclusive, to a position opposite the second level of contacts in the associated contact field, the normal post springs 25'! are opened and then reclosed. These normal post springs remain closed until the selector switch I2 is released. when the trunk I8 is seized through the second or an evennumbered contact level of the selector switch I2 or any other selector switch, low-resistance relay R325 is energized in the trunk test circuit which now includes the test or release conductor I811. This relay remains energized until the hold relay R3I0 restores during the release of the connector switch I3. In operating, the relay R325 closes its contacts 326 to prepare the operating circuit for the slow-to-release pulse circuit outwit relay R335. Thereafter, and when the wipers 390 to 393', inclusive, of the connector switch I3, are positioned to engage the contacts IE5 at the end of-the third digit dialed at the calling station A, the relay R310 operates in the manner previously explained to complete an alternative circuit for energizing the lower windings of the two relays RI I0 and RIZII in series. This circuit extends from ground by way of the contacts SB'I and 370, the conductor I8e, the wiper 264, the contacts ZII, the normal post springs 25?,the conductor "lie, the control path through the line switch I I, the contacts I and IE6, the. lower winding of RIII], and the lower winding of R626 to battery. .It will be noted that the lower winding of the wipe out relay R200 is excluded from this circuit. Accordingly, the current traversing the lower winding of the marginal relayRI20 is sumcient to cause the operation of this relay. In operating, the relay RIZIJ locks to ground over. a path including the contacts I2I and I 32. At its contacts I23, the relay RIZD opens a point in the common portion of thepreviously traced operating circuits for the relays RIEILRIGIJ and RI30. At its contacts I22, the relay RIZU prepares an alternative operating circuit for the release relay RI30.

The transfer relay RI I0, in operating, initiates the operation of the pulse sender I5 to transmit a train of ten restoring pulses to the operating magnets of the selected, indicators in the exact manner described above; Incident to the transmission of this train of restoring pulses, the display drums of the selected indicators are restored to their respective normal or blank positions.

From the preceding explanation it will also be recalled thatafter the train of restoring pulses is transmitted from the pulse sender I5, the relay R520 restores to cause the sequential operation of the two relays R5I5 and R5I0, the relay R320 restores, and the relay R350 completes its operation. Upon fully operating, the relay R350 closes its contacts 355 to complete the prepared operating circuit for the relay R335. The relay R335,

in operating, opens its contacts 330 to prevent a current pulse from being transmitted to the operating magnets of the ,units indicators in the selected display units during the release of the connector switch I3. During the period separating the operation of the relay R5I5 and the operation of the relay R5I0, a circuit including the contacts 5MB, 5 and I22 is completed for energizing the release relay RI30. Thus it will be apparent now that, with the reset pulse cut-ofi relay RI20 operated, the three transfer relays RI50, RIM and R540 are prevented from operating incident to the operation of the pulsesender I5. Wit the relay R5 restored, the relay R530 is prevented from operating, to initiate the operation of the rotary switch 560 in the manner previously described.

In operating the relay RIBS locks to ground over a path includingthe contacts I34, 5! I v and 5I8. At its contacts I82 and I35, the relay Rlt0 opens the operating and locking circuits for the relays HI I 0 andRIZII, and the circuit for energiz'ing the pilot lamps I05. At its contacts I33, the relay Rite opens another point in the common portion of the initially traced operatingcircuits for itself and the two relays RIM) and RISO.

, I are energized.

The transfer relay RI I0, upon restoring, opens its contacts H2 and IM to interrupt the loop circuit extending to the line relay R399 of the connector switch I3. When this loop circuit is opened the connector switch I3, the selector switch I2 and the line switch II are caused to release, in the exact manner explained above. In this regard it will be apparent that the two relays R325 and R335 are deenergized and restore in response to the release of the hold relay R3Ill, Upon restoring, the relay RI It] also opens its contacts III to deenergize the relays R500, R505, R5I5 and R5). When these four relays restore the pulse sender I5 is fully released. Incident to the operation of the relay R5Iil and the release of the relay R5I5, the previously traced locking circuit for the relay RI3I is opened to deenergize the last-mentioned relay. When the relay RI3U restores, all of the equipmentutilized in wiping out the indications displayed by the indicators of the display unit 25, and the corresponding units of the other boards, is'released. From the above explanation it will be apparent that in order for any doctor to wipe out the indications displayed by the indicators provided for his use, he may dial, at any control station of the system, a number which is one hundred greater than his assigned directory number. More specifically, the wipe out number for any doctor difiers from his reset number only in the first digit, the first digit of the wipe out number being one greater than the first digit of the assigned reset number.

In considering the operationof the doctor paging facilities provided in the system, it may be assumed that while the doctor No. 165 is occupied with duties on a particular fioor of the hospital a call for this doctor is received by the operator attending the P. B. X. switchboard Iil. In order to transmit this information to the doctor No. 165, the operator at the switchboard ID actuates the key I65e to its off-normal position wherein a marking path is completed for impressing ground potential upon the contact I65cZ of the contact field embodied in the illustrated connector switch I3 and the corresponding con tacts of the other connector switches having access to the indicators provided for the use of this doctor. With the apparatus in this condition if the doctor No. 165 proceeds to the first floor, for example, and operates the transmitting device IElIa to set up a connection through the line switch II, the selector switch I2 and the connector switch I3 to the display unit 26 and the corresponding display units of the other boards, a circuit is completed for energizing the signal control rela R360 immediately after the third digit of the doctor's identification number s dialed at the station A. More specifically, this circuit is completed by way of the contacts 311, the wiper 393 and the contacts of the key I652, when the transfer relay R310 operates at the end of the dialing operation. In operating, the relay R388 opens its contacts 36I to interrupt the previously traced circuit over which the pilot lamps At its contacts 362, the relay R368 completes a circuit including the pulsing lead 325 for intermittently energizing the pilot lamps I55. It will be noted that this circuit is completed each time the pulse generator 325 operates to transmit a ground pulse over the pulsing lead 326. Aside from the intermittent energization of the pilot lamps I05 to produce a flashing signal at the first floor stations A and B, the

control of the selected indicators to wipe out the existing display, and possibl reset the indicators to display new indications, and the release of the switching equipment, are accomplished in the -exact manner described above. In this regard, it will be noted that the signal control relay R368 is deenergized in response to the release of the transfer relay R3?!) at the end of the cycle of operation of the pulse sender I5. During the period when the pulse sender is operating to transmit restoring and reset pulses to the operating magnets of the selected indicators, the intermittent energization of the pilot lamps I continues. The flashing signal which resuits, seiwes to inform the calling doctor No.

that he is wanted by the operator attending the P. B. X. switchboard It. Upon receiving this information the doctor No. 165 may proceed to the nearest telephone and call the switchboard operator for instructions or information.

Although the invention has been explained with reference to a system for indicating the location of doctors attached to the stafi? of a large hospital, it wi l be understood that the system may also be used in industrial and other organizations to indicate the location of other objects, both animate and inanimate, which may be in zoned areas that are not necessarily different floors of a building. For example, the system may be utilized for indicating at one or more points the different locations of the executives and department heads of a large industrial organization having buildings disposed at random Within a confined area. As a further example, the system may be used to indicate the location of loaded inter-departmental trucks which are used in an industrial organization and are moved from place to place to meet production or other manufacturing requirements. In order generically to designate the persons or movable objects, the locations of which are to be indicated; such persons or objects have been termed subjects in certain parts of the following portions of the specificaion.

While there has been described what is at present considered to be the preferred embodiment of the invention, it will be understood that various modifications may be made therein. and it is contemplated to cover in the appended claims all such modifications as fall within the true spirit and scope of the invention.

What is claimed is:

1, In a system for indicating the location of a plurality of subjects which may be located in different zones of a plural zone area, a display board including display units individually corresponding to said subjects, anautomatic selector switch having access to said units for control purposes and including outlet contacts individually corresponding to said subjects, marking paths extending to said outlet contacts, a control station including a signal device and means for directively controlling said automatic switch to select one of said display units, means operative in response to the selection of said one unit for resetting said one unit to display an indication of the zone in which the corresponding subject may be located or for wiping out an indication previously displayed by said one unit, and. means selectively controlled over one of said marking paths from said signaling station for energizing said signal device.

2. In a system for indicating the location of a plurality of subjects which may be located in different zones of a plural zone area, a plurality of tion and indicating positions for displaying the difierent digits of plural digit number's identifying said zones, restoring pulse circuits individual to the sets of indicators, resetting pulse circuits individual to said indicators, a control station in. said area, automatic switching equipment directively controllable from said stationto select a set of said indicators, an automatic plural digit pulse sending device associated with said station and operative successively to transmit a train of restoring pulses and a plurality of trains of reset pulses, means operative in responseto the selection of said one set of indicators for connecting said sender to control the pulsing circuits individual to the selected indicators, transfer means for directing the restoring pulses to the restoring pulse circuit individual to the indicators of the selected set and for directing the pulses of the successively transmitted reset trains to the reset pulse circuits individual to different indicators of the selected indicator set, and

means selectively controllable from said control station for preventing reset pulses from being transmitted to the indicators of the selected set. 3. In a system for indicating the'location of a plurality of subjects which may be located in diilerent zones of a plural zone area, a display board including display units individual to said subjects and each including an indicator for displaying an indication of the zone in which the corresponding subject may be located, a control station in said area, tandem related selector and connector switches each having a plurality of different settings, means at said control station for directively controlling said switches to select one of said display units for control purposes, and means selectively controlled in accordance with the setting of said selector switch after said one display unit is selected for either resetting the indicator of the selected unit to display a new indication or for operating the indicator of the selected unit to wipe out the indication displayed thereby.

4. In a system for indicating the location of a plurality of subjects which may be located in difi'erent zones of a plural zone area, a plurality of pulse controlled indicators arranged in sets which are individual to said subjects, a control station in said area, tandem related selector and contion, an automatic selector switch directively controllable from said stationto select any one of said units and including outlet contacts individual to said units, means including circuits individually including different ones of said outlet contacts selectively controlling selected ones of said units to wipe out indications displayed thereby or to set up new indications therein which indicate the zones in which the corresponding subjects may be located, a signaling station, a signaling circuit extending between saidstations and having branches individual to said subjects which respectively include diiierent ones of said outlet contacts, and means at said signaling station for selectively completing the branches of said circuit.

control any one of said display units, a signal at nector switches each having a plurality of different settings, means at said control station for directively controlling said switches to select one set of said indicators and to set up restoring and reset pulsing circuits to the indicators of the selected set, an automatic plural digit sending device associated with said station and including means for transmitting successively a train of restoring pulses and a plurality of trains of reset pulses, means operative in response to the selecsaid station, and means included in said selector switch for controlling said signal to provide an indication that the particular person controlling said switch is wanted in a pre-determined zone-oi said area in response to operation of said selec tor switch to the setting corresponding to said particular person. I

'Z. In a system for indicating the location of a plurality of persons who may be located in different zones of a plural zone area, a display board including display units individual to said persons and each controllable to provide an indication of the zone in which the corresponding persons may be located, a control station, an automatic selector switch having settings individually corremeans at said signaling station for selectively rendering said last-named means effective to control said signal.

a. in an indicating system, a plurality of display units, an automatic selector switch having clih'erent settings individually corresponding to different persons who may use said system and including means for controlling difierent ones or said units when operated to the difierent settings thereof, a pair'of stations, a signal at oneor said stations, means controllable by a person at said one station for directing said selector switch to any one 01' the settings thereof, means included in said 'one switch for controlling said signal to provide a predetermined indication to a given person at said one station when said given person effects the operation of said selector switch to the setting individual to said one, person, and means at the other of said stations for selectively rendering said-last-named means efiective to control said signal.

THOMAS H. MO'IE. 

